Often, as a result of various medical procedures or certain types of illness, it becomes impossible for a patient to ingest nourishment orally. In many such situations, it becomes necessary to administer nourishment directly to the digestive tract, either at a site in the stomach or directly into the proximal segment of the small bowel. For example, recent studies indicate that post operatively, patients can maintain much of their own healing abilities if they receive ample nourishment shortly after the operation. Since oral feeding is often not possible, the use of a suitable feeding apparatus becomes essential for a quick recovery.
Devices used to administer nourishment enterally must meet several criteria in order to be effective. The device should be easy to operate to assure proper use by individuals unfamiliar with the device or even by the patient himself. Nevertheless, though simple to operate, the device must also be able to accurately dispense a predetermined amount of liquid and have safety features in order to avoid overfeeding.
Among the first feeding devices were plastic bags, similar to those used in plasma and blood transfusions. With these devices, the rate of flow was adjusted by varying the height of the feeding unit above the patient and by adjusting a constricting device attached to the tubing leading to the patient. One drawback of using this device was the inability to accurately determine the amount of nourishment being administered during a set period of time and the resultant need to frequently monitor the delivery. In addition, since there was direct communication between the bag and the patient, there was always the threat of overfeeding. If bags with only a small volume were used, overfeeding could be avoided but the need to frequently replace empty feeding units would again be very time consuming.
In response to these shortcomings, a variety of feeding type devices were developed. The complexity of these devices increased to a point where operation by untrained or inexperienced individuals was almost impossible. Many of these devices used liquids or gases in order to pressurize the fluids being administered, thereby seeking to obtain greater degrees of accuracy in measuring the amount of nourishment provided over a given period of time. Other devices utilized complex electrical or electromechanical means in order to measure and pump the liquids into the patient. By increasing the complexity of these devices, there has also been a concomitant increase in the risks of error, either from actual failures of the devices or mistakes by personnel responsible for operating the devices.
There is presently a need for a simple yet effective feeding unit, which although being easy to use, also incorporates the necessary safeguards against overfeeding. This is especially true since in some situations, a patient may return home while still receiving nourishment through either a jejunostomy feeding tube, a long-term nasogastric tube, or a similar apparatus. Providing a simple yet effective feeding unit not only allows the patient to safely treat himself at home, but also removes much of the anxiety which comes from the patient or family member operating relatively complex equipment.
Since these individuals are seeking to return to a more normal lifestyle, it is also preferable for them to self-administer their nourishment in a manner which mimics normal eating patterns as much as possible. Thus, devices which provide small quantities of nourishment at a constant rate over an extended period of time are undesirable. For these situations, it is preferable to mimic normal feeding patterns by administering a bolus of food in a relatively short period of time and then allowing the body to go through its normal digestion and absorption processes.
Another factor which needed to be taken into consideration was that of cost. Not only would reducing the cost of a feeding unit broadly benefit the medical industry by reducing medical costs, but it would also aid the individual patient without proper insurance coverage. In order to develop a simple, yet effective, feeding device, I began with an analysis of the basic plastic bag type feeding device. My object was to overcome the previously mentioned shortcomings without significantly complicating the basic device. I also sought to retain the advantages of the basic bag structure. These devices were easy to use and were inexpensive enough to be disposable which is important for maintaining sterile conditions. When I finally divided the bag by adding a center sheet of material, I began to appreciate the possibilities in having a multichambered unitary device. Shortly thereafter, I developed the subject invention.
It is, therefore, an object of this invention to provide a feeding unit capable of delivering predetermined amounts of nourishment accurately.
It is another object of this invention to provide a feeding unit which can be effectively operated by untrained personnel and only requires a minimal amount of attention.
Another object of this invention is to provide a feeding unit having safeguards against overfeeding.
Another object of this invention is to provide a device in which the amount of liquid to be administered at one time can easily by varied.
Another object is to provide an invention which is capable of delivering the nourishment as a bolus within a relatively short period of time.
Another object of this invention is to provide a device wherein the speed of delivery of the bolus from one of the feeding chambers to the patient is independent of the flow rate from a reservoir into the adjacent feeding chamber.
Briefly, the present invention accomplishes the above purposes by providing a unitary structure consisting of three sheets of inextensible material. These sheets are sealed so as to form four compartments, two of which are larger and are used as a reservoir and as a coolant container, and the other two of which are used as alternate feeding chambers. The divider between the feeding chambers acts as a common wall and is sufficiently flaccid so as to allow either of the chambers to have a maximum value which is equal to the maximum combined value of both chambers. A control means alternates the flow of fluid to and from the chambers so that while the fluid in one chamber is flowing to the patient, fluid from the feeding solution reservoir is flowing into the other chamber.